1. Field of the invention
The present invention concerns an assembly of accumulator cells juxtaposed to form a unit provided with holding means to facilitate handling it.
The unit must be readily demountable if it is necessary to change a cell. Assembly and demounting operations must not require the use of any special tools.
The assembly must have overall dimensions as close as possible to those of the cells constituting it.
Finally, it must have a service life of 10 to 15 years in environmental conditions that may be severe.
2. Description of the prior art
Various types of assembly are already in routine use.
In a first known type assembly the accumulator cells are juxtaposed and merely surrounded by adhesive tape. The assembly is demountable, but re-assembly involves the provision of a special adhesive tape. What is more, there is no adhesive that can be guaranteed for the service life mentioned above. An assembly of this kind does not comprise any holding means and handling it is therefore impractical.
In a second known type assembly the accumulator cells are encircled by a metal or plastics material strap that is fastened with clips or a metal strap that is welded. Demounting is simply a matter of cutting the strap, but re-assembly after replacing a cell entails using a special banding or welding machine, with the risk of the cells being damaged through excessive binding forces.
In a third known type assembly the accumulator cell containers are formed with dovetails on their vertical edges. Metal clips are used to interlock adjacent cells. The dovetails at the two ends of the unit enable holding means to be fixed on. This assembly has disadvantages. The thermoplastics materials used to mold the cell containers are not well able to withstand the mechanical loads resulting from the convex angular shapes of the dovetails, which are difficult to mold, or the localized forces exerted by the metal parts during handling.
An object of the present invention is to avoid these disadvantages and to provide an assembly of accumulator cells in a unit that is easy to transport, demount and re-assemble and handling of which does not apply any localized stresses to the accumulator cell containers or covers.